Influence of reactant concentration and reaction time in the chemical modification process of polypropylene by p-phenylen-bis-maleamic acid in the melt

Following earlier studies on chemical modification processes of polypropylenes by polar monomers, a new study by grafting p-phenylen-bis-maleamic acid in the molten state has been carried out. In a previous work a four independent variable Box–Wilson experimental design lets us conclude the adequacy of working at a certain gear rate and low times of reaction. This is the reason why, in this work, a two independent variable design (reactant concentrations) has been used and applied to four different times of reaction in order to check those findings. Besides, it is also confirmed that the process follows an oscillating evolution of grafting level with the reaction time, and the existence of critical points for the reactant concentrations (p-phenylen-bis-maleamic acid and dycumile peroxide). These facts seem to agree with a chemisorption mechanism, governing the reaction yields in this kind of reactive systems, where the main and limiting role is played by the macromolecular substrate.